(a) Field of the Invention
The present invention relates to plasma display devices, and more particularly, to a plasma display device configured to prevent horizontal image streaking or a horizontal luminance difference induced by a luminance difference between scan electrodes.
(b) Description of the Related Art
Generally, a plasma display device includes a plasma display panel (PDP) for displaying an image, a chassis base for supporting the PDP, and a plurality of printed circuit boards (PCBs) mounted on the chassis base and connected to the PDP.
The PDP generates plasma using gas discharge, excites phosphors using vacuum ultra-violet rays emitted from the plasma, and realizes an image using red, green, and blue visible lights that are generated as the excited phosphors are stabilized.
In order to induce the gas discharge, the PDP includes address electrodes and display electrodes (e.g., sustain electrodes and scan electrodes). The address electrodes intersect the display electrodes at regions corresponding to discharge cells. The address electrodes, the sustain electrodes, and the scan electrodes are connected to the corresponding PCBs through flexible printed circuits (FPCs).
Typical PCBs include a sustain board for controlling the sustain electrodes, a scan board for controlling the scan electrodes, and an address buffer board for controlling the address electrodes. The scan board is connected to the scan electrodes through a scan buffer board having scan integrated circuits (scan ICs) mounted thereon.
A plurality of FPCs connect the scan electrodes of the PDP to the scan buffer board. The scan electrodes are classified into a plurality of groups, and each of the plurality of FPCs is connected to each group of the scan electrodes, respectively.
Each of the FPCs includes two outermost lines, and inner lines disposed between the outermost lines. With reference to one FPC, each of the outermost lines has a first side to which no inner line is adjacent and a second side to which an inner line is adjacent. The inner lines have a first side to which an inner line or an outermost line is adjacent and a second side to which an inner line or an outermost line is adjacent.
Accordingly, each outermost line is influenced by a magnetic field induced from only one inner line. That is, the magnetic field permeating to one side has an effect on the outermost line. On the other hand, each inner line is influenced at both sides by the magnetic field induced from the inner lines, or the inner line and the outermost line. That is, the magnetic field has an effect on each of the inner lines from both sides thereof.
Thus, the voltage waveform influenced by the magnetic field permeating to one side is applied to each scan electrode connected to the outermost lines. In comparison, the voltage waveform influenced by the well-balanced magnetic field at both sides is applied to each scan electrode connected to the inner lines.
Thus, the scan electrodes connected to the outermost lines have high impedance and generate low luminance, as compared to the scan electrodes connected to the inner lines.
With regard to two FPCs adjacent to each other, scan electrodes connected to outermost lines of first and second FPCs continuously generate relatively low luminance, as compared to the scan electrodes connected to the inner lines.
In the whole plasma display panel, portions between two FPCs have relatively low luminance and the portions are regularly formed. This is called horizontal image streaking (or horizontal luminance difference) of the PDP.